Petros - From Greek name Petros "stone", "boulder" which is met in all the Christian languages (Latin Petrus, Italian Pietro, German Petrus, Peter, Russian Pyotr). It comes from Bible. The short forms are Peto, Petik and Potos. From all of them surnames are formed.
Avakyan - is a name of Armenian origin. It derives from the Armenian word avag, meaning "oldest", perhaps signifying that a male ancestor was a prominent individual in his community. It may also mean "son of Avak".